This July 17, 2012 photo released by the U.S. Geological Survey shows adult female walruses on an ice flow with young walruses in the Eastern Chukchi Sea, Alaska. A remote plateau on the Arctic Ocean floor, where thousands of Pacific walrus gather to feed and raise pups, has received new protections from the Obama administration that recognize it as a biological hot spot and mark it off-limits to future oil drilling. (AP Photo/U.S. Geological Survey, S.A. Sonsthagen)

WASHINGTON -- A number of environmental groups are asking the Department of the Interior to rescind permission granted to Shell to begin exploratory drilling in the Arctic this summer because they say the company's plan would not adequately protect the walrus.

In particular, Shell's plan would violate federal rules limiting how closely a company can drill multiple wells, Earthjustice argued in a letter to Interior Secretary Sally Jewell, sent on behalf of 10 other groups. The rules, issued in 2013 by the Fish and Wildlife Service under the Marine Mammal Protection Act, state that such drilling operations should be at least 15 miles apart in order to "avoid significant synergistic or cumulative effects from multiple oil and gas exploration activities on foraging or migrating walruses." But Shell's two proposed drill sites are only 9 miles apart, the groups said.

"We ask you to take immediate action to address this basic deficiency in Shell’s drilling plan and permit applications, protect the Pacific walrus, and ensure agency decisions resulting from the review of Shell’s drilling proposal are defensible and lawful," wrote Earthjustice.

Annie Leonard, executive director of Greenpeace USA, argued in an email to HuffPost that the Obama administration must "not let an oil company make up its own rules in the Arctic." Greenpeace is one of the groups that joined Earthjustice's letter.

"Knowingly violating regulations intended to protect the Pacific walrus is just another example of how Shell is willing to put ecosystems and communities at risk with this reckless plan," Leonard said. "It's time for President Obama to take control of this situation before catastrophe strikes."

Shell did not respond to a request for comment, but a spokeswoman told Alaska Public Media that the company is consulting with federal officials on the terms of their authorization before drilling begins.

"[The Fish and Wildlife Service] is reviewing Shell's program to ensure compliance with all applicable laws," an official with the Interior Department told HuffPost. "Their review will ensure that measures are in place to minimize potential disturbances to walrus and other marine mammals."

Jamestown, the birth of a nation 400 years ago. The ships Discovery, (L), and the Susan Constant, (R), are moored to a pier at Jamestown settlement in Jamestown, Virginia on April 6, 2007. (MANNIE GARCIA/AFP/Getty Images)